1. Field of the Invention
The present invention relates to a flash unit for use with a camera.
2. Description of the Prior Art
A flash unit for flash photography is ordinarily constructed as a separate accessory which is mounted on a camera body when needed. Hence a camera user may forget to carry a flash unit with him, and in such case must forego its use. In order to avoid this inconvenience, cameras incorporating flash units therein have been proposed. However, such cameras are necessarily larger than corresponding cameras that have been built as compactly as possible. In fact, cameras with built-in flash units may be quite cumbersome as compared to cameras without such units. Moreover, in manufacture, adapting a camera for built-in flash requires extensive redesign of the camera body to receive the flash unit. Effectively, the project requires an entirely new mechanism.
Generally speaking a compactness in size and light weight are important features in a photographic camera. Various complicated mechanisms and devices are housed in a very compact manner within a camera body. This leaves little extra space therein large enough to receive a flash unit. Thus, housing a comparatively large flash unit a compact camera. Inevitably make the size of camera body large. Also changes in design of various complicated mechanisms and devices built in a camera body and development of a new mechanism are needed to prevent the size of said camera body from becoming too large. This noises the cost of camera solely for housing a flash device in a camera.
Also, when a flash device is housed in a camera body, said flash device will be positioned comparatively close to the camera's objective lens. The angle formed between a line connecting the flash device with an object and the optical axis of the lens is then very small. When the subject is a person, this often produces so-called "red eye." That is, the eyes of a person photographed in a finished color print appear red.
This "red eye" phenomenon occurs while a portion of the light generated by a flash device is reflected by eyes of the subject and back to the taking lens when the angle formed by the line connecting a flash device with an object and the optical axis of the taking lens is small. In other words it appears when the position of the flash device is close to the objective lens.